Fish Habit May Reduce Breast Cancer Risk, Study Suggests

THURSDAY, June 27 (HealthDay News) -- Regularly eating oily fish such as salmon, tuna or sardines may help reduce the risk of breast cancer, a new report suggests.

These fish contain a type of fatty acid known as n-3 polyunsaturated fatty acids (PUFAs).

"Increased n-3 PUFA intake has a protective effect for breast cancer," said researcher Duo Li, a professor of nutrition at Zhejiang University in Hangzhou, China.

Li and his team reviewed 21 different studies that looked at the intake of fish and PUFAs. The previously published research included more than 800,000 women in the United States, Europe and Asia, and 20,000 cases of breast cancer. The follow-up time varied, from four years to 20.

The new report is published online June 27 in the journal BMJ..

Fish include several types of PUFAs that are involved in chemical messaging in the brain, helping to regulate both blood vessel activity and the immune system. The fatty acids also have been linked with other health benefits, such as lower risk of heart problems.

Earlier studies have shown conflicting results about the protective effects of PUFAs that are found in fish and breast cancer risk. So Li decided to pool the results of the 21 studies and reanalyze them.

In his analysis, consumption of most types of PUFAs -- but not fish itself -- was linked with a lower risk. Women with a high intake of PUFAs had a 14 percent reduction in breast cancer risk. For every 0.1-gram-per-day increase in the intake of the fatty acids, there was a 5 percent lower risk of breast cancer, the study found.

So how much fish should you eat? "One to two servings of oily fish per person per week is suggested," Li said.

Li said he can't explain with certainty the association between PUFAs and lowered breast cancer risk. Among other possibilities, he speculated that the fatty acids may help regulate the activities of molecules involved in cell growth and in the spread of cancer cells.

Two U.S. experts who reviewed the new findings saw pros and cons to the report.